I currently have a 2 server DAG internally in the office. This is healthy and working. I want to host a 3rd member offsite in another state so in the event that the office power is out, a disaster occurs, and so on, mail will continue to flow, users can access email via smart device, laptop, etc. I'm sure this is a pretty general question, but how do I proceed??!! I have access to a colo and I can setup a VPN between the 2 sites if need be. Will I need a DC at the offsite location as well as Exchange? I"m sure mail flow can be managed with MX records and I've come across some 3rd party apps that can act as an https redirector for OWA.